The thrust of this proposal is the development of a compact, inexpensive, epithermal neutron source for clinical use in boron neutron capture therapy (BNCT). The scope of this proposal encompasses the entire system including a linear accelerator (linac) to accelerate an intense proton beam, a lithium target to convert the proton beam into neutrons, and a moderator assembly to optimize the neutron flux for clinical use. The proposal draws upon the most recent development in linac technology, namely the development of the Rf Focused Drift tube (RFD) linac structure. The thrust here will be to develop a continuous wave (cw) version of this innovative structure. Other technical innovations will include the pursuit of a solid lithium target that can withstand 50 kW of proton beam power and a moderator assembly to optimize the intensity, shape and energy spectra of the neutron fluxes for clinical applications, while reducing the associated gamma-ray fluxes. Efforts will be made to converge on a reliable and cost effective approach to this demanding need. The long-term objective of this proposal is to provide the medical community with practical, hospital-based sources of epithermal neutrons to support the growth of the promising BNCT modality of cancer treatment. PROPOSED COMMERCIAL APPLICATION: This research will lead to a new family of compact, reliable, cost effective, linac-based, neutron sources for a variety of neutron-hungry applications such as boron neutron capture therapy (BNCT), thermal neutron radiography (TNR), thermal neutron activation analysis (TNAA), non- destructive testing (NDT), and explosive detection systems (TNA and PFNA).